1. Technical Field
The present invention relates to a vehicle drive device provided with a left wheel drive unit for driving a left wheel and a right wheel drive unit for driving a right wheel.
2. Description of the Related Art
In JP-A-2010-235051, a vehicle drive device is described which is equipped with a left wheel drive unit having a first electric motor for driving a left wheel of a vehicle and a first planetary gear transmission provided on the power transmission path between the first electric motor and the left wheel, and also equipped with a right wheel drive unit having a second electric motor for driving a right wheel of the vehicle and a second planetary gear transmission provided on the power transmission path between the second electric motor and the right wheel. In the first and second planetary gear transmissions, the first and second electric motors are respectively connected to the sun gears thereof, the left wheel and the right wheel are respectively connected to the planetary carriers thereof and the ring gears thereof are connected to each other. Furthermore, the vehicle drive device is provided with braking means for braking the rotation of the ring gears by releasing or engaging the connected ring gears and is also provided with a one-way clutch.
According to JP-A-2010-235051, the vehicle drive device configured as described above is used as a rear wheel drive unit, another drive unit, i.e., a front wheel drive unit, powered by an engine is provided for the front wheels. During high-speed travel in which engine efficiency is high, the front wheel drive unit is used as a drive source. Furthermore, the state of the braking means of the rear wheel drive unit is switched from its engaged state to its released state to prevent the first and second electric motors 2A and 2B from rotating at over speed.
In recent years, demands for energy saving and improvement in fuel efficiency, demands for improvement in comfort, etc. have been increasing, and the vehicle drive device described in JP-A-2010-235051 also has room for improvement in controllability.